Duke Nukem 3D Easter Egg - The Nukem Redemption

In episode 1.lvl 3, the prison level, there is a prison cell with a poster of a woman in it. Behind the poster is a tunnel that leads outside the prison. This is from the movie The Shawshank Redemption, where a man in prison digs an escape tunnel. To hide it, he covers the hole with a poster of a woman. I didn't notice until now.

Samuel R